Bad PCM 2005 ls2?

[1967ls2]

2005 GTO LS2 in a 1967 RS/SS Camaro.

So I noticed my vehicle was hesitating & I had a misfire. I scanned it and it said that there was a misfire at cylinder five and possibly a coil primary or secondary issue.

These are the things I have done to fix/diagnose.

Replaced both o2 sensors (haven't replaced and thought it was time anyways)
Replaced plug wires
Swapped coils
Swapped coil packs from both sides
Swapped plugs
Checked the continuity from cylinder five coil wire from the white plug that plugs into the coil harness with the correct pin that connects to the pcm.
I bought an inductive wire tester so I can check to make sure I'm getting spark when the vehicle is running.

It's like I drive it around, the car drives fine for a while then starts missing. This happened today, so I did the majority of the testing referenced above, plugged it all back in, cleared the codes, fired it up and checked and cylinder five was hitting again fine. However every time I drive it around for a while the misfire at cylinder five will come back.

Any other suggestions as to what could be causing this intermittent issue?

[mitch_04]

Might not hurt to pop a valve cover and check for a mechanical issue. We had a Chevy pickup that was similar, would code a certain cylinder misfire but not all of the time. Turned out it was a broken valve spring. Never made noise, would just misfire occasionally once it was warmed up.

[1967ls2]

Thanks for the response.

I can understand the misfire under that condition but when it is misfiring and I put the conductive spark tester to the plug wire, it is intermittently sending signal to the plug itself.

Makes me think it is the actual pcm.

[GMTech]

While anything is possible, the PCM is very reliable and rarely the cause of this type of concern. My thought would be to check each individual wire going to the coil. There are four wires at the coil plug, a black wire at terminal A (ground), a brown wire at terminal B (low reference), a green wire at terminal C (control) and a pink wire at terminal D (ignition). While the ground, low reference, and ignition wires are shared with the other coils on this cyl. head it is still possible to have a problem between the splice and the coil plug. I would check each individual wire while the cylinder is misfiring. You can do this by back probing the wires. You could also wiggle test the harness and connector. Drag testing the terminals in the connector with a matching terminal similar to the ones in the coil is also a good test.

[1967ls2]

Thanks for the reply. I'm going to try to check the wiring more like you suggest to see if I can chase it down before replacing the pcm. I just bought a new standalone harness and installed less than a year ago which is why I was thinking it wasn't the harness.